Building panels of wood provided with a mechanical locking system are known and disclosed in, e.g., WO03/087498.
Furthermore, building panels provided with a mechanical locking system comprising a displaceable and resilient tongue cooperating with a tongue groove for vertical locking are known and disclosed in, e.g., WO2006/043893. The tongue is a separate part and is made of, e.g., plastic, and positioned in an insertion groove at an edge of a panel. The tongue is pushed into the insertion groove during a vertical assembling of the panels and springs back into the tongue groove of an adjacent panel when the panels have reached a locked position.
Although the description relates to floor panels, the description of techniques and problems thereof is applicable also to other applications, such as wall panels, ceiling panels, furniture, etc.
A drawback with the known building panels that are provided with a mechanical locking system is that a gap may arise between two adjacent building panels which are locked together, when the moisture content of the building panels decreases. The mechanical locking system may also break down due to an asserted tension load that is caused by the decrease of the moisture content.
The above description of various known aspects is the applicant's characterization of such, and is not an admission that any of the above description is considered as prior art.